Effect of space flight on bone strength.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to E R Morey.
Explore the source record for details and available documents.
Parameters of bone formation and resorption were measured in rats orbited for 19.5 days aboard the Soviet Cosmos 782 biological satellite. The most striking effects were on bone formation. During flight, rats formed significantly less periosteal bone than did control rats on the ground. An arrest line at both the periosteum and the endosteum of flight animals suggest that a complete cessation of bone growth occurred. During a 26-day postflight period, the defect in bone formation was corrected. No significant changes in bone resorption were observed.
Phosphate depletion causes significant changes in the composition of the cell population in bone and the metabolic activities of these cells. The data presented indicate that a vitamin D metabolite has a significant role in producing the increase in osteoclast number associated with phosphate depletion. The increased resorptive activity and number of osteoclasts leads to a marked increase in the rate of bone resorption resulting in the liberation of calcium phosphate, while the decrease in the rates of the processes involved in bone formation (matrix production, osteoid maturation, and mineralization) reduces the amount of phosphate which is removed from the circulation. Thus, all of the effects of phosphate depletion on bone are consistent with the interpretation that bone acts as a reservoir of phosphate and is used to maintain soft tissue and serum phosphate levels at the expense of bone.
Explore the source record for details and available documents.